Heretofore, spent nuclear fuel has been placed in fuel storage casks which are typically stored above ground, at various locations in the continental United States. These storage areas are typically in restricted areas, and security is provided to protect the casks from possible tampering or the removal of any spent nuclear fuel. At present, the only indication of possible reactor spent fuel diversion from a storage cask is provided by means of tamper-indicating tags and seals which are provided with each of the storage casks.
With the increasing risk of terrorist acts within the United States, and the possibility that spent nuclear fuel sources might by sought after and diverted for possible terrorist acts, a renewed effort has been undertaken to identify means by which spent nuclear fuel storage casks may be readily inspected to determine whether spent nuclear fuel which has been stored within same has been removed improperly from the storage cask.